The term “Flash Freezing” generally refers to a refrigeration process that will quickly freeze a product. It is desirable to be able to quick-freeze many different materials but particularly biological or medical materials, in order to avoid deterioration or to place the material quickly into condition for transport or use.
Some forms of prior flash freezers make use of liquid bath to facilitate quick freezing. However, this requires liquid handling, which is undesirable. Further the liquid typically used in flash freezing processes is expensive and the mechanisms used to circulate the liquids are expensive and maintenance intensive.
Extreme low temperature “walk in” type freezers are also used for flash freezing. Such freezers are made to operate at sub-zero temperatures and provide adequate but non-uniform freezing times. Articles placed at different locations within the freezer compartment can have significantly different freezing times.
A need is therefore realized for a fast acting freezer that can make use of existing conventional freezer technology without using liquid, liquefied gases or other materials other than air.
Another problem with typical flash freezers is that the freezer unit is typically a stand alone, single function unit that cannot be used for other than flash freezing materials. Often a walk-in type conventional freezer is provided in the same laboratory or facility where the flash freezer is located, and takes up physical space in addition to the space occupied by the flash freezer.
Attempts have been made in the past to combine the function of a conventional refrigeration unit to facilitate flash freezing. However such units have not been satisfactory in that the freezing fluids are typically not appropriately circulated to assure uniform freezing times.
The present invention, as will be understood below, provides a new and nonobvious solution to the above problems. And, while achieving the benefits derived from other known methods and devices, the present invention avoids the shortcomings and detriments individually associated therewith.